After chemical or electrical excitation, neurons sequentially express and accumulate a battery of early response gene (ERG) mRNAs which code for cytokines, cell surface receptors, critical enzymes and transcription factors (TF). These genes mediate and control neuronal responses to stress. Despite their importance, only a small number of brain specific ERGs have been identified and cloned. In response to this RFA for nervous system gene discovery, we will apply a novel affinity method for the selective and direct isolation of brain ERG mRNAs based upon their 3' untranslated region, AUUUA instability repeats. Using this technology, we have prepared a cDNA library from activated lymphocytes which contain a variety of known ERG cDNAs as well as a substantial number of unknown cDNAs which potentially code for uncharacterized ERG cDNAs. Therefore, we propose to isolate mRNA from resting and kainic acid treated mouse brain and hippocampus and 1). Produce AUUUA selected, ERG cDNA libraries; 2). Partially sequence all clones in the libraries and identify unique cDNAs; 3). Isolate full length cDNAs coding for novel ERGs and 4). Characterize the expression patterns of novel ERGs in mouse brain by in situ hybridization. In aggregate, these studies will identify heretofore unknown, ERGs induced by seizure and begin to characterize the temporal and spatial expression of these genes in the brain.